1、Designation: C1795 17Standard Test Methods forHigh-Temperature Characterization of Gypsum Boards andPanels1This standard is issued under the fixed designation C1795; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods describe three bench top test meth-ods for measuring the thermophysical responses of gypsumboards and pa
3、nels when exposed to high temperatures. The testmethods are:1.1.1 High-temperature Core CohesionThis test methodevaluates the ability of the test specimen to withstand aspecified mechanical strain while exposed to elevated tempera-ture.1.1.2 High-temperature ShrinkageThis test method evalu-ates dime
4、nsional changes in the test specimen when exposed toelevated temperatures.1.1.3 High-temperature Thermal InsulationThis testmethod evaluates the rate of heat transfer through the thicknessof the test specimen by measuring the length of time requiredto heat the center of the test specimen over a spec
5、ifiedtemperature rise when exposed to prescribed furnace condi-tions.1.2 The test methods appear in the following order:Test Method SectionHigh-temperature Core Cohesion 4High-temperature Shrinkage 5High-temperature Thermal Insulation 61.3 UnitsThe values stated in either inch-pound units orSI units
6、 (given in parenthesis) are to be regarded separately asstandard. The values stated in each system may not be exactequivalents; therefore, each system shall be used independentlyof the other. Combining values from the two systems mayresult in non-conformance with the standard.1.4 While these tests a
7、re useful for evaluating fire propertiesof gypsum boards and panels, they are not suitable forpredicting the Test Methods E119 fire resistance performanceof a specific gypsum protected assembly that has not previ-ously been tested in accordance with Test Methods E119 andcorrelated to these tests.21.
8、5 This standard is used to measure and describe theresponse of materials, products, or assemblies to heat andflame under controlled conditions, but does not by itselfincorporate all factors required for fire hazard or fire riskassessment of the materials, products, or assemblies underactual fire con
9、ditions.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.7 Thi
10、s international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade
11、(TBT) Committee.2. Referenced Documents2.1 ASTM Standards:C11 Terminology Relating to Gypsum and Related BuildingMaterials and SystemsE119 Test Methods for Fire Tests of Building Constructionand MaterialsE631 Terminology of Building Constructions2.2 Other Standards:EN 520 Gypsum PlasterboardsDefinit
12、ions, Requirementsand Test Methods3. Terminology3.1 GeneralRefer to Terminologies C11 and E631 forstandard terminology on gypsum and related buildingmaterials, systems and building construction.3.2 Definitions of Terms Specific to This Standard:1This test method is under the jurisdiction ofASTM Comm
13、ittee C11 on Gypsumand Related Building Materials and Systems and is the direct responsibility ofSubcommittee C11.01 on Specifications and Test Methods for Gypsum Products.Current edition approved June 1, 2017. Published June 2017. Originallyapproved in 2005. Last previous edition approved in 2015 a
14、s C1795 15. DOI:10.1520/C1795-17.2Shipp, P. H., and Yu, Q., “Thermophysical Characterization of Type X SpecialFire Resistant Gypsum Board,” Proceedings of the Fire and Materials 2011Conference, San Francisco, Jan. 1, 2011 Feb. 2, 2011, Interscience Communica-tions Ltd., London, UK, pp 417-426.Copyri
15、ght ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of Internation
16、al Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.1 Thermal Insulation Index (TI), na single value indexthat denotes the rate of heating at the center of the ThermalInsulation Test specimen as determined by the elapsed ti
17、me tothe nearest minute for the temperature to rise from 104 to392F (40 to 200C).4. High-temperature Core Cohesion4.1 Summary of Test MethodThe high-temperature corecohesion of gypsum panel products is evaluated by applying ashear force and bending moment to a cantilevered test speci-men by hanging
18、a weight from the free end of the specimen.The specimen is exposed to heating from two burner flames ata specified distance and location from its fixed end. Theexposure of the specimen to the burner flame results in thecalcination of the specimen, which weakens the core matrixand results in deflecti
19、on of the loaded, cantilevered specimen.When a specified deflection occurs, the specimen is examinedfor breakage. This test is derived from an earlier version of thehigh-temperature core cohesion test found in EN 520.4.2 Significance and UseThis test method provides aprocedure for evaluating the hig
20、h temperature strain capacityof gypsum panel products.4.3 Apparatus:4.3.1 Specimen Mounting DeviceA fixture capable ofrigidly supporting the specimen and weight in the horizontalplane. The specimen is clamped or otherwise held rigidly atone end in a cantilevered horizontal position. The mountingfixt
21、ure shall provide sufficient clearance of the end weightfixture above the horizontal base to allow for the full prescribeddeflection of the specimen. (Figs. 1 and 2).4.3.2 Hanger StrapA bracket for suspending a weightfrom the free end of the test specimen consisting of anL-shaped metal strap constru
22、cted of 20 gauge sheet metal orother suitable material. The short leg of the strap is 0.65 60.05 in. (16 6 1 mm) in length. The long leg of the strap hasa mounting hole drilled in it near the outer extremity and is ofsufficient length that the hook or wire by which the loadingweight is suspended fro
23、m the strap does not contact thespecimen.4.3.3 Loading WeightA weight fitted with a hook or wirefor hanging it from the free end of the specimen by means ofthe hanger strap. The loading weight may be configured as acup or disk to receive weighted shot or slotted disks to adjustthe weight for differe
24、nt test specimen thicknesses. The totalweight of the entire loading device (hanger strap, loadingweight, suspension wire or hook) shall correspond to thenominal thickness of the sample in accordance with Eq 1,rounded to the nearest integer multiple of 25, and shown inTable 1:4.3.4 PlatformAn adjusta
25、ble height platform to limit thedeflection of the specimen to the specified distance of 0.4 60.05 in. (10 6 1 mm) (See Fig. 1.)4.3.5 Heating System:FIG. 1 Side View of Core Cohesion Test ApparatusW 5 10.6St0.50D(1)Where:W = Total weight of loading device, oz., andt = Nominal board thickness, in.TABL
26、E 1 Required Loading Device Weight for Each BoardThicknessNominal Board Thickness Weight of Loading Device12 in. (12.7 mm) 10.6 0.4 oz (300 10 g)58 in. (15.9 mm) 13.2 0.4 oz (375 10 g)34 in. (19.1 mm) 15.9 0.4 oz (450 10 g)C1795 1724.3.5.1 Two propane Meker burners having a nozzle diam-eter of 1.14
27、6 0.04 in. (29 6 1.0 mm) and a gas orifice of 0.036 0.01 in. (0.76 6 0.25 mm) are mounted horizontally withtheir nozzles facing each other (Figs. 2 and 3).4.3.5.2 The axes of the burners are aligned to within 0.05 in.(1 mm).4.3.5.3 Needle valves at the base of each burner provide forfine adjustment
28、of the gas flow rate to control flame shape andtemperature.4.3.5.4 Natural gas or propane is supplied to each burnerfrom a single source via a tube with a Y fitting. A pressureregulator to control the pressure and a pressure gauge tomeasure the pressure are installed in the line between thesource an
29、d the Y fitting. The gas pressure supplied to the Yfitting shall be 0.5 6 0.1 psig (3.5 6 0.7 kPa). A flow metermay optionally be installed to aid in monitoring and maintain-ing consistent gas flow rates (Fig. 4).4.3.5.5 The burners are adjusted to produce stable, pre-mixed flames with the character
30、istic blue zone of the flamecovering the entire screen area at the mouth of the burner andprojecting38 618 in. (10 6 3 mm) from the burner. Beyondthe blue premixed zone, both flames project horizontally in aturbulent deflagration contacting the specimen near its bottomedge with little or no vertical
31、 deflection due to buoyancy orforced convection in the space between the burner and wherethe flame strikes the test specimen perpendicularly.The zone ofheating extends from the bottom edge of the specimen upwardsto the top edge.FIG. 2 Top View of Core Cohesion Test ApparatusFIG. 3 Alignment of Burne
32、rs and Thermocouples with Respect to Test SpecimenC1795 1734.3.6 ThermocouplesInsulated chromel-alumel thermo-couples (Type K)116 in. (1.6 mm) diameter stainless steelsheathed, ungrounded tip 36 ga.4.3.6.1 The thermocouples are aligned horizontally with thetop of the burners and secured to the burne
33、r with a hose clamp(Fig. 3).4.3.7 Gauge Blocks, 0.2 in. (5 mm), 0.4 in. (10 mm), and1.0 in. (25.4 mm).4.3.8 StopwatchTiming device capable of measuringelapsed time in one second intervals or less.4.4 SamplingTest specimens shall be taken from thesample lot of gypsum panel products as indicated in 4.
34、5.4.5 Test Specimens:4.5.1 Cut six specimens from the gypsum board sampleusing a saw to insure straight, square edges.4.5.2 Each specimen shall be 12.0 6 0.1 in. (300 6 2 mm)long by 1.75 6 0.05 in. (45 6 1 mm) wide, with the edges ofthe specimen not less than 4 in. (100 mm) from any edge of thefull
35、gypsum board sample. Specimens can be tested when cutfrom any orientation from the sample board for specificevaluation but since the orientation can contribute to themeasured results, the orientation must be identified and re-corded for each test result. Common orientations for evaluationare the lon
36、g edge of the specimen parallel to the paper-boundor long edge of the board as manufactured or the long edge ofthe specimen parallel to the end perpendicular to the paper-bound or long edge of the board as manufactured.4.6 ConditioningCondition specimens to constant weightat a temperature of 85 6 15
37、F (29.5 6 8.5C) and relativehumidity 50 6 2%.4.7 Procedure:4.7.1 Clamp one end of the test specimen in the supportingdevice in a cantilever configuration. The long edge extendslengthwise 10.25 6 0.05 in. (260 6 1 mm) from the supportpoint to the free end of the test specimen. The short edge of thete
38、st specimen is vertical (Figs. 1-3).4.7.2 Align the lower edge of the test specimen to the lowestpoint of the burner nozzles (Figs. 1 and 3).4.7.3 Position the mid-point of the burner nozzles 4.0 60.05 in. (100 6 1 mm) from the point of support (Figs. 1 and2).4.7.4 Position the mouth of each burner
39、nozzle 1.0 6 0.05in. (25.4 6 1 mm) from the adjacent specimen face by meansof a gauge block (Figs. 2 and 3).4.7.5 Position each thermocouple parallel to the upper edgeof the burner and 0.2 6 0.05 in. (5 6 1 mm) from the specimenface by means of a gauge block (Figs. 2 and 3).4.7.6 Place the hanger st
40、rap on the free end of the cantile-vered test specimen, 10.25 6 0.05 in. (260 6 1 mm) from thesupport point of the mounting device, and suspend the loadingweight from it. The total weight of the suspended load shall beas specified in 4.3.3.4.7.7 Adjust the height of the platform so that the distance
41、from the platform to the bottom of the suspended load is 0.4 60.05 in. (10 6 1 mm) above the surface of the platform. Verifythe spacing by means of a gauge block (Fig. 2).4.7.8 Open the gas valve, start the stopwatch and ignite bothburners.4.7.8.1 Adjust the gas flow so that the temperature at eacht
42、hermocouple is 1832 6 90F (1000 6 50C).4.7.8.2 Both flames shall be stabilized at the specifiedtemperature with the characteristic appearance described in4.3.5.5 within 60 s of lighting the burners.4.7.9 The test is over when the specimen deflects downwardand the load comes into contact with the sur
43、face of theplatform.4.7.9.1 At the conclusion of the test, stop the stopwatch andshut off the burners.4.7.9.2 Visually inspect the specimen immediately aftershutting off the burners.4.7.9.3 Observe if the specimen has broken into two or moredistinct pieces at or before the time at which the load con
44、tactedthe platform.4.7.9.4 Record the elapsed time from the start to the end ofthe test and whether or not the specimen was broken into twoor more distinct pieces.FIG. 4 Schematic of Gas Supply to BurnersC1795 1744.7.10 Repeat steps 4.7.1 4.7.9.4 of the procedure for eachof the six test specimens fr
45、om the gypsum panel productsample.4.8 ReportReport the number of specimens that remainedintact, the number of specimens that broke into two or moredistinct pieces, and the time to reach 0.4 in. (10 mm) deflectionfor each specimen.4.9 Precision and BiasNo information is presented abouteither the prec
46、ision or bias of this test method for measuringhigh-temperature core cohesion since the test result is qualita-tive.5. High-temperature Shrinkage Test5.1 Summary of Test MethodThis test method evaluateshigh-temperature shrinkage of gypsum panel products byexposing specimen disks to prescribed temper
47、ature conditionsin a muffle furnace and measuring the change in diameterbefore and after heating exposure.5.2 Significance and UseThis test method evaluates thehigh-temperature shrinkage of gypsum panel products and isuseful for estimating their behavior when exposed to fire.5.3 Apparatus:5.3.1 Dril
48、l Presscapable of running 620 rpm.5.3.2 Hole Sawnominal 4 in. (100 mm) outside diameterwith pilot drill bit removed.5.3.3 FurnaceBox furnace with PID control, 2012F(1100C) maximum temperature, 3500 W power, 240 VAC,volumetric capacity 0.65 cu. ft. (18.4 l) with interior dimen-sions 1499in.(356 229 2
49、29 mm) and no exteriorpenetrations or vents.3,45.3.3.1 The furnace shall be capable of temperature controlof 610F (65C) up to and including 930F (500C) and618F (610C) for temperatures exceeding 930F (500C).5.3.4 Hearth PlateCeramic tray, made of vitreous alumi-nosilicate fiber insulation or equivalent refractory material tosupport test specimen loads.5.3.5 Digital Electronic or Dial CaliperDiameter measur-ing device, 0-6 in. (0-152 mm) range, 0.001 in. (0.025 mm)graduation.5.3.6 Specimen PedestalsSix pedestals,
